132 THE VOYAGE OF H.M.S. CHALLENGER. 



consists of two rows of spindles converging towards the margin of the calyx, which, for 

 the rest, have the same form and size as the spindles of the coenenchyma. Their size 

 averao-es 0"9 by O'l ; 0'89 by 0"067 mm. Each of the eight longitudinal bauds projects 

 spine-like somewhat above the margin of the calyx. The tentacular operculum is formed 

 of spicules of which two always lie in the base of each tentacle, converging towards its 

 apex. When the tentacles are folded these close together in a conical, convex operculum. 

 These spicules measure 0'43 by 0"04 ; 0'4 by 0"05 mm. Small spicules occur also in the 

 more distal 2Dortion of the tentacle, measuring 0'2 by 0"5 mm. and less. The spicules of 

 the tentacles are spindle-shaped, somewhat flattened and curved, covered with small, 

 scattered, upright, pointed warts. 



The colour of the entire colony is greyish-white ; the axis is brown. The colony is 

 densely covered with a species of Cortjne, which forms over it quite a felted coat. 



In the thickness of its coenenchyma and in its entire habit, which recalls rather 

 Paramuricea, this species differs very considerably from the other species of the genus, 

 which are usually graceful and have a thin coenenchyma. The shaj^e and armature 

 of the calyces and the structure of the spicules show, however, such a close agreement 

 with the other species of Muricella, that one may without hesitation refer it to this genus. 



Habitat. — Station 190, Arafura Sea; depth, 49 fathoms; bottom, green mud. 



Genus Elasmogorgia, n. gen. 

 ? FUigeUa, Gray, Ann. and Mag. Nat. Hist., ser. 4, vol. ii. p. 443, 1868. 



This genus has been established for a small Muriceid, with a flexible, horny axis, 

 which is covered by a thin but not transparent coenenchyma. The polyps rise at large 

 intervals, and at right angles to the stem. They are short and bluntly conical. The 

 tentacles are quite retractile, and when in a state of repose the margin of the calyx is 

 quite infolded over them. 



The terminal portions of the branches are truncated and without polyps. The 

 spicules are broad, somewhat straight, warty spindles ; sometimes curved spindles 

 0"2 to 0"G mm. long; wdiich lie close to one another and occur both in the coenenchyma 

 and in the polyps. In the coenenchyma the S2:)icules seem to be longitudinally placed ; 

 on the polyps they extend from the base to the oral region. The tentacles are armed 

 with rough spiny spicules on their basal portions, which, when the tentacles are retracted, 

 form an opercular covering, but this can be completely withdrawn into the body, so as 

 to leave no outward trace. The only example found has a delicate flexible stem, from 

 which one branch is given off". The stem is of the same diameter throughout, and is so 

 flexible that it can be bent and twisted like a piece of twine. It is just possible that 

 the form may be identical with that described by Dr. Gray as Filigella gracilis (loc. 

 cit.); but the description leaves much to be desired, and in the absence of the type 



